Hi Leo,


I absolutely see no problem in the fact that Aperture is depending on Sesame.

As a matter of fact, since we will be getting Sesame “for free” by getting Aperture through the IP process, I completely agree with you and think that we should use Sesame in SMILA to build our Ontology Service on top of it.


The motivation to use Sesame in SMILA is not solely based on the circumstance that Aperture is bringing it along.

Other important factors are:

1.       License compatibility to EPL

2.       Its triple store implementation seems to do a good job

3.       It has no large 3rd-party dependencies – this is critical for the IP process


Important note:

Of course we will implement our Ontology Service in that way so that (e.g. in some commercial SMILA-Installations) it will be possible to replace Sesame with some other triple store implementation if needed.


Best Regards



Von: smila-dev-bounces@eclipse.org [mailto:smila-dev-bounces@eclipse.org] Im Auftrag von Leo Sauermann
Gesendet: Montag, 26. Januar 2009 15:35
An: Smila project developer mailing list
Cc: aperture-devel@lists.sourceforge.net
Betreff: Re: AW: [smila-dev] Re: [Aperture-devel] Aperture bundlization forSMILA


It was Daniel.Stucky@empolis.com who said at the right time 26.01.2009 15:17 the following words:

Hi all,
some more comments inline. (It's getting confusing :-) )

I cut down the length..... I am looking at the other mail by Antoni *right now*
he has some points ... will answer later... one thing about RDF now:

aperture is a SEMANTIC framework (as the S in SMILA :-),
so we build on RDF,
= sesame has to stay in or nothing will work in aperture.
theoretically, it can be exchanged by Jena, because we are based on
but you don't want to look into their own private hell of ~10mb of
I know that aperture is based on RDF, I hoped that for just using extractors no RDF store was required. I still think it is not used anyway, but some implementations just come with this jar. 
On the other hand this offers Smila a ready to use rdfstore, which will be needed in the near future. This is nice.

Ha, truth is:
we use the Sesame implementation's in-memory RDF containers!
(called memoryrepository).

We use these containers everywhere!
also in the extractors.
see also:

We use the in-memory models as a kind of "complex hashmap that does all the RDF tricks including sparql", which is the way to go, which is clever, and "good".
To pass around RDF from one place in the framework to another, this in-memory representation is perfect.
Also we need Sesame to actually create the data - we use RDF2go and sesame
inside the extractors and crawlers to express the information.

Aperture as such does *not* use the disk-backed storage model of sesame,
although projects built on aperture may do.

For SMILA we will have the same problem:
how to hande  in-memory RDF.
You need parsers, serilaizers, inferencers,
sparql, programming API, in-memory model, etc etc etc
I know about this, but I have no time to spent in SMILA to manage a working group to do it,
so best would be if someone picks up the ball there,
the best solution would be to just copy the Aperture model (rdf2go and sesame) for now,
and then use it for a while until SMILA has gathered enough experience with RDF
to bake its own.

Just for the records:
we thought about making a JSR for RDF2Go long ago,
Henry Story from SUN just loved the idea.
but confronted with the overwhelming work that THIS would take
(= multiple manyears) we quickly gave up on this idea.
of course, sooner or later a JSR for handling RDF in memory
and a JSR for RDF storage abstaction will hopefully evolve,
and if you weigh me in gold to pay for these man-years I would even
be eager to work in such a standardization group ;-)


DI Leo Sauermann       http://www.dfki.de/~sauermann 
Deutsches Forschungszentrum fuer 
Kuenstliche Intelligenz DFKI GmbH
Trippstadter Strasse 122
P.O. Box 2080           Fon:   +49 631 20575-116
D-67663 Kaiserslautern  Fax:   +49 631 20575-102
Germany                 Mail:  leo.sauermann@dfki.de
Prof.Dr.Dr.h.c.mult. Wolfgang Wahlster (Vorsitzender)
Dr. Walter Olthoff
Vorsitzender des Aufsichtsrats:
Prof. Dr. h.c. Hans A. Aukes
Amtsgericht Kaiserslautern, HRB 2313